The Duration

Traditionally a performance last an entire night, starts soon after sunset with an overture (talu) of gamelan music and continues without a break until dawn. The audience is not expected to sit silently, people meet friends and talk to them, look around, sometimes they get a snack from the stall, those who need to rest take a nap, the point being not the content of the story but the ritual efficacy of the performance. Sometimes people regard the puppets themselves as being entered by spirits during the performance; and a good dalang (puppeteer) is often said to be entranced.
From experience everyone more or less knows how a wayang play will proceed, and the exciting parts that they like to watch: the fight scenes and, in particular, the moment when the hero appears with his servants (panakawan) at midnight. According to tradition, any one at wayang performance is safe from evil influences which normally plague people, even though they may be so far from the screen that they can barely hear the voice of the dalang.